Here's some bottom line stuff. A copper mod like the Akuma is superb but i don't take it out & about. If your precious about keeping it shiny you can clean it in vinegar (Just did mine & it came up nice) but copper is a soft metal & so scratches easy. Personally i'm good with that & it looks good a bit battered & nothing lasts forever.
If you want a good quality all rounder maybe you should go for a stainless steel job. If it's a goody & has decent contacts (Silver/plate or copper) & a sensible switch system for a hassle free life then you can't go wrong. Then it's about the the one one you prefer most. The voltage drop thing imo is only relevant if you want to go proper low resistance 9Like Raggs does & that's a different game), otherwise it's completely pie in the sky.
Take a look on airborne int/myvape & there's some wicked mods on there. Shipping is quick & prices are good.